Search PubMed⌕ Search

Biomedical subjects

M Brugh

Publications and source records attributed to M Brugh.

16 recordsLinked to original sources
PubMed1979

Immunization of chickens and turkeys against avian influenza with monovalent and polyvalent oil emulsion vaccines.

Chickens and turkeys vaccinated with inactivated virus oil-emulsion vaccines containing different concentrations of either 1 (monovalent) or 4 (polyvalent) strains of avian influenza virus (AIV) were challenged-exposed with virulent AIV A/chicken/Scotland/59 or A/turkey/Ontario/7732/66. Four of 6 vaccines protected completely against postexposure mortality. Vaccine valency did not alter the serologic and challenge-exposure responses of chickens vaccinated with AIV A/turkey/Wisconsin/68, which was the virus component common to both monovalent and polyvalent vaccines. The magnitude of the serologic responses and protection against challenge-exposure were dependent on the concentration of virus in the vaccines. These data indicate that control of virulent AIV in chickens and turkeys by vaccination with inactivated vaccines may be feasible.

Animals↗
PubMed1978

Inactivated Newcastle disease vaccines: influence of virus concentration on the primary immune response.

Inactivated vaccines of high potency could play a valuable role in Newcastle disease control programs. We determined the influence of virus concentration and method of concentration on the immune response of chidkens to inactivated vaccines. We used the LaSota strain of virus concentrated by either ultracentrifugation of polyethylene glycole precipitation. Virus concentration has a significant effect (P less than or equal to .01) on serum antibody levels at 2, 3, 4, and 6 weeks after vaccination; but during this same period, the antibody response was not significantly influenced by method of concentration. Virus concentration increased beyond 2000 hemagglutination units did not significantly increase (P greater than or equal to .05) the magnitude of the antibody response.

Animals↗
PubMed1977

Butylated hydroxytoluene protects chickens exposed to Newcastle disease virus.

Dietary butylated hydroxytoluene, an antioxidant widely used in food and feed processing, prevents mortality of chickens exposed to virulent Newcastle disease virus and prevents the serological response of chickens exposed to avirulent Newcastle disease virus. This chemoprophylactic effect is evident when chickens are fed diets containing concentrations of butylated hydroxytoluene normally used for antioxidant purposes (100 to 200 parts per million of total diet).

Animals↗
PubMed1977

Reactivation of Newcastle Disease Virus Neutralized by Antibody.

In an effort to improve current technology for detection of Newcastle disease virus in convalescent birds, a procedure has been developed for efficient reactivation of virus that has been neutralized by antibody. The reactivation capabilities of fluorocarbon treatment, ultrasonic treatment, pH extremes, and proteolytic digestion were evaluated using the LaSota strain of virus. Reactivation was maximum after proteolytic digestion with either trypsin or papain, and reactivation effciency was up to 100%, depending on the enzyme used for digestion and the amount of antibody in the neutralization mixture. Reactivation at pH extremes was considerably less efficient than reactiviation by proteolytic digestion, and neither fluorocarbon nor ultrasonic treatments effectively recovered antibody-neutralized Newcastle disease virus.

Antibodies, Viral↗
PubMedDate not supplied

Simulation of maternal immunity by inoculation of immune yolk preparations into the yolk sac of 1-day-old chickens.

Yolk harvested from eggs laid by hens hyperimmunized with killed Newcastle disease virus (NDV) was inoculated into the yolk sac of 1-day-old specific-pathogen-free (SPF) chickens. Serum hemagglutination-inhibition antibody titers reached maximum levels 1 to 4 days after yolk inoculation and declined at a rate similar to that reported for naturally acquired maternal antibody. Expected levels of immune interference were observed when yolk-inoculated chickens were vaccinated with a conventional oil-emulsion NDV vaccine. These results show that yolk-sac inoculation with yolk antibody is a suitable approach for producing maternally immune chickens for laboratory studies.

Animals↗
PubMedDate not supplied

Re-evaluation of the pathogenicity of A/chicken/Alabama/75 (H4N8) influenza virus.

Avian influenza (AI) virus A/chicken/Alabama/7395/75 (H4N8), a putatively non-pathogenic virus associated with a self-limiting outbreak of severe disease in commercial layers, was selectively passed in chickens or in cell cultures and then in chickens to determine whether virus with increased pathogenicity would emerge. When 20 derivatives of the parental virus were each inoculated intranasally and intratracheally in leghorn hens, mortality rates ranged from zero (0/24) to 25% (6/24); mortality was 4% (1/24) for hens inoculated with the parental virus. Many virus reisolates (51/144) from hens that died exhibited high pathogenicity, killing at least six of eight intravenously inoculated 4-week-old chickens. Most derivatives examined produced plaques in trypsin-free cell cultures more efficiently than the parental virus, but the highest plaquing efficiencies observed (10%) were lower than would be expected (100%) for highly pathogenic subtype H5 or H7 AI viruses. These results confirm that the Alabama H4N8 virus can acquire increased pathogenicity upon passage in chickens and suggest that it may have acted alone in producing the severe disease observed in laying chickens in Alabama.

Animals↗
PubMedDate not supplied

Amantadine resistance among hemagglutinin subtype 5 strains of avian influenza virus.

Several avian influenza virus strains of hemagglutinin subtype 5 were assayed for sensitivity to the antiviral drug amantadine. Most strains exhibited little sensitivity to the drug as measured by plaque reduction. The A/Chicken/Scotland/59 (CS59), however, was highly sensitive, making it easily distinguishable from the other H5 strains. Drug sensitivity of the viruses was also assayed in chicken embryos. The in ovo patterns of amantadine sensitivity differed from those detected in cell culture. The CS59 isolate could not be distinguished from all the other strains on the basis of its response to amantadine in ovo. Although amantadine protected chickens inoculated with CS59 from morbidity and mortality, drug-resistant viruses were readily isolated from the infected birds. As found with other amantadine-resistant variants, the structure of the matrix gene was altered in the resistant isolates. These results demonstrate that amantadine resistance is widespread among avian influenza viruses of the H5 subtype, that drug sensitivity in cell culture does not necessarily reflect responses to amantadine in ovo and in vivo, and, as previously found, amantadine-resistant derivatives of H5 strains may be isolated from birds protected by the drug.

Amantadine↗
PubMedDate not supplied

Emergence of highly pathogenic virus during selective chicken passage of the prototype mildly pathogenic chicken/Pennsylvania/83 (H5N2) influenza virus.

The prototype mildly pathogenic A/chicken/Pennsylvania/21525/83 (H5N2) avian influenza virus, which was isolated more than 5 months before the emergence of highly pathogenic virus in the major 1983 Pennsylvania outbreak, was examined for the presence of minority subpopulations of highly pathogenic virus. Selective serial passage of the parental mildly pathogenic virus in leghorn hens did not lead to recovery of highly pathogenic virus. However, several highly pathogenic reisolates were recovered from hens inoculated with either of two mildly pathogenic virus clones selected for their ability to efficiently produce plaques in trypsin-free chicken embryo fibroblasts. Unlike the parental virus, these reisolates caused high mortality in chickens and produced postmortem lesions typical of highly pathogenic avian influenza. Electrophoretic mobilities of the hemagglutinin glycoproteins of the highly pathogenic derivatives resembled those of the prototype highly pathogenic A/chicken/Pennsylvania/1370/83 (H5N2) virus isolated in October 1983. These results suggest that unrecognized subpopulations of highly pathogenic virus may have infected Pennsylvania chickens for several months before emerging as the clinically manifest component of the virus population.

Animals↗
PubMedDate not supplied

Preparation of inactivated oil-emulsion vaccines with avian viral or Mycoplasma antigens.

The influence of the composition of water-in-oil emulsions on their physical characteristics was determined by preparing experimental emulsions with various water-to-oil ratios and various emulsifiers. Emulsions containing Tween 80 in the aqueous phase and Arlacel A or Arlacel 80 in the oil phase were lower in viscosity than emulsions containing only an oil-phase emulsifier. Viscosity decreased as the concentration of oil increased. Oil-emulsion vaccines prepared with aqueous- and oil-phase emulsifiers had low viscosity, were stable for more than 12 weeks at 37 C, and induced a marked primary antibody response in chickens.

Animals↗
PubMedDate not supplied

Use of the Nobuto blood-sampling paper strip for Newcastle disease serology.

Dried whole blood collected by the paper-strip method of Dr. Kenzo Nobuto was evaluated for use in the Newcastle disease hemagglutination-inhibition (HI) test. When dried blood on the Nobuto strip was eluted in 1.0 ml of diluent, the resulting HI titers were similar to titers obtained with sera diluted 1:10. Both storage time and temperature influenced the stability of HI activity in dried blood, though the influence was minimal and is considered to have little significance in diagnostic serology, The advantages of this method of blood collection for Newcastle disease HI tests are discussed.

Animals↗
PubMedDate not supplied

The influence of test conditions on Newcastle disease hemagglutination-inhibition titers.

Replicate samples of serum from chickens immune to Newcastle disease were titrated to determine the influence of certain test conditions on hemagglutination-inhibition (hi) titers. The test conditions studied were those most likely to vary in normal laboratory operations. The most marked effect on magnitude of HI titers was incubation time of twofold serum dilutions in antigen-saline; the average titer increase after incubation of the serum-antigen mixture for 1 hr at 37 C was log2 2.3 (fivefold). Twofold increases in virus concentration of the antigen-saline diluent caused an average titer reduction of log2 0.8. Shifts in HI titers were only minor with twofold changes in erythrocyte concentration (log2 0.3), with variations of test reading times from 0.5 to 2.0 hr (log2 0.1), and with variations in the period between preparation of the initial 1:10 serum dilution in antigen-saline and the subsequent serum dilutions (log2 0.3).

Animals↗
PubMedDate not supplied

A simple method for recording and analyzing serological data.

Titration endpoints from any 2-fold dilution series represent either true or modified base-2 logarithms and can be recorded conveniently by tube or dilution number. The simple arithmetic mean of titers thus expressed can be easily converted to geometric mean titer (GMT) by use of a table of antilogarithms, which is presented. This approach not only facilitates the handling of large volumes of data but also simplifies GMT calculation.

Animals↗